Universities in Wales "could lose" millions of pounds after student cap change
Universities in Wales say they could lose £7.1m to English institutions by 2015/16 if more university places are made available there.
In December, Chancellor George Osborne announced that a cap restricting how many students English universities could recruit would be lifted.
Higher Education Wales said this could result in 1,500 students leaving to study over the border next year.
The Welsh government said it was too early to assess the impact on Wales.
From September an extra 30,000 places will be made available in England for 2014/15 and 60,000 places in 2015/16.
Currently, Welsh students who study outside of Wales pay the first £3,500 of their tuition fees, while the Welsh government pays the rest.
With English universities charging £8,000 a year on average in tuition fees, this costs the Welsh government £4,500 per student.
This means the 7,370 students from Wales who will start university courses in other parts of the UK this year could take more than £33m with them - money which could otherwise be used in the higher education sector here.
A document sent to Higher Education Wales (HEW) says the changes could see an extra £7.1m go to English institutions by 2015/16.
The paper, leaked to BBC Wales, calculates that between 2% and 2.5% of students in England are from Wales, so by 2015 an extra 1,500 students could leave to study over the border.
Last year Prof Colin Riordan, chairman of HEW, said that if the money the Welsh government currently paid in tuition fee grants to other UK countries was spent in Wales, it could be used to improve their research capacity and upgrade the support available to students.
In November, Education Minister Huw Lewis announced a major review into higher education and student finance.
He said it was right to take stock at a time of "rapid and unpredictable change" facing universities.
Responding to the leaked document to HEW, the Welsh government said changes to student number controls in England would not necessarily result in a higher numbers of Welsh students choosing to study over the border.
"When we know more we'll be in a position to comment further, but at this point we're not convinced that this decision is sustainable in the long term and there's nothing to suggest applications to Welsh HEIs (higher education institution) will be affected," said a spokesman.
"Supporting higher education continues to be a priority for us, and in 2014/15 over £362m will be made available to Welsh universities via the Higher Education Funding Council for Wales (HEFCW).
"A recent WAO (Wales Audit Office) report confirmed that thanks to our tuition fee policy, income to the higher education sector in Wales will continue to grow, from £1.26bn in 2011/12 to £1.45bn in 2015/16, despite the cuts imposed on us by the UK government."
Officials in the Welsh government also point out that more money comes into Welsh universities with English students than which leaves Wales - and that Welsh institutions get above-inflation increases in funding every year.
Dr David Blaney, HEFCW chief executive, said the proposed 30,000 increase in places in England in 2014/15 was likely to create further opportunities for prospective students, including those domiciled in Wales, to study in England.
"It is, though, too soon to be clear about the scale of the impact of these changes in terms of the additional number of Welsh domiciles who will be accepted at English universities," he added.